This invention relates to a security protection system for protecting a motor vehicle both against theft by hijacking and theft while the vehicle remains unattended in a parked position. There are numerous patents in the prior art which address the problem of theft of a parked vehicle, but few address the problem of hijacking. In theft by hijacking, the owner is accosted by an armed thief while approaching the parked vehicle or while preparing to drive off and forced to surrender the vehicle. Being in a state of panic the owner is in no position to take any protective action for his or her vehicle, the only thought in mind is to surrender the vehicle without suffering physical harm and fleeing to safety.
When faced with a hijacking situation, it is in the best interests of the victim to let the hijacker drive off with the vehicle, thereby avoiding possible physical harm. It is also in the interest of the vehicle owner to have the vehicle disabled without travelling too far from the point of theft.
The hijacking problem is addressed in U.S. Pat. No. 5,172,094, issued Dec. 15, 1992 to David M. Stadler. A passive protection system is disclosed wherein opening of a vehicle door or an attempt to start the vehicle motor initiates a predetermined time cycle. If a reset signal is not received before the end of the time cycle, a vehicle disabling circuit is set which is activated by pressing the brake pedal.
U.S. Pat. No. 4,107,543, issued Aug. 15, 1978 to Neil B. Kaplan, shows a passive vehicle anti-theft system utilizing a combination of condition responsive switching components which are automatically armed as the authorized user leaves the vehicle and closes the last vehicle door. This system does not employ a timing device to provide for disablement of the vehicle within a controlled time period.
While the prior art does teach automatically armed anti-theft vehicle protection systems useful for hijacking protection, none of the prior art shows a totally armed system providing a period of partial disablement before final engine shutdown as accomplished by the present invention. It is desirable to provide a partial disablement to give the hijacker an opportunity to get out of traffic and maneuver the vehicle to the side of the road before the engine is turned off.